doubly linklist

1. Task: Define doubly linked .
code:
#include "stdafx.h"
#include<conio.h>
#include<iostream>
using namespace std;
class double_linklist
{
private:
struct node
{
int data;
node *prev;
node *next;
}*p;
int c;
public:
double_linklist()
{
p=NULL;
c=0;
}
bool isempty()
{
return(p==NULL);
}
void addatbeg(int num)
{
c++;
node *n;
n=new node;
n->data=num;
n->prev=NULL;
if(p==NULL)
{
n->next=NULL;
p=n;
}
else
{
n->next=p;
p->prev=n;
p=n;
}}
void addatend(int num)
{
c++;

2. node *n;
n=new node;
n->data=num;
n->next=NULL;
if(p==NULL)
{
n->prev=NULL;
p=n;
}
else
{
node *temp=p;
while(temp->next!=NULL)
{
temp=temp->next;
}
n->prev=temp;
temp->next=n;
}
}
void addafter(int num,int location)
{
if(isempty())
cout<<"Doubly link list is empty!!!"<<endl;
else if(c<location)
cout<<"Location not found!!!"<<endl;
else
{
c++;
node *n,*temp=p;
n=new node;
n->data=num;
while(1<location)
{
temp=temp->next;
location--;
}
temp->next->prev=n;
n->next=temp->next;
temp->next=n;
n->prev=temp;}}
void del(int num)
{
if(isempty())
cout<<"Doubly link list is empty!!!"<<endl;
else
{
node *temp=p;
while(temp!=NULL)
{

3. if(temp->data==num)
{
if(temp==p)
{
if(c==1)
p=NULL;
else
temp=p=p->next;
p->prev=NULL;
}
else if(temp->next==NULL)
{
temp->prev->next=NULL;
}
else
{
temp->next->prev=temp->prev;
temp->prev->next=temp->next;
}
c--;
}
temp=temp->next;}}}
void display()
{
if(p==NULL)
cout<<"Doubly link list is empty!!!"<<endl;
else
{
node *temp=p;
cout<<"Doubly link list elements are : "<<endl;
while(temp!=NULL)
{
cout<<temp->data<<" ";
temp=temp->next;}}}
void count()
{
cout<<"Total no of nodes is : "<<c<<endl;
}
~double_llist()
{
node *temp;
while(p!=NULL)
{
temp=p;
p=p->next;
delete temp;}}};
int _tmain(int argc, _TCHAR* argv[])
{
double_llist d_linkllist;
int c,num,location;

4. while(1)
{
cout<<"nDoubly linked list menu : "<<endl;
cout<<"n1.add at end of listn2.add at beginning of listn3.add after
specific in listn4.del from the list";
cout<<"n5.display the listn6.count total nodes of the
listn7.exit"<<endl;
cout<<"Enter your choice : ";
cin>>c;
switch(c)
{
case 1:
{
cout<<"Enter value : ";
cin>>num;
d_llist.addatend(num);
break;
}
case 2:
{
cout<<"Enter value : ";
cin>>num;
d_llist.addatbeg(num);
break;
}
case 3:
{
cout<<"Enter value : ";
cin>>num;
cout<<"Enter location after which you want to enter value : ";
cin>>location;
d_llist.addafter(num,location);
break;
}
case 4:
{
cout<<"Enter value : ";
cin>>num;
d_llist.del(num);
break;
}
case 5:
{
d_llist.display();
break;
}
case 6:
{
d_llist.count();
break;

5. }
case 7:
{
cout<<"You are exiting....."<<endl;
system("pause");
exit(0);
break;
}
default:
cout<<"Invalid choice!!!"<<endl;}}
system("pause");
return 0;}
Output: